Apple order number MC007LL/A / 27" 2560x1440 pixel display

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Display flickers briefly then goes black after connecting mini dp

The display was working one night just fine until we restarted the machine. When the machine booted up, the display remained black.

I tested it on a macbook that is working with another cinema display, but nothing happened. I opened up the broken display and reattached the cable connecting to the function port on the logic board. After trying it again, it would flicker and I would see my desktop for a split second before the screen goes black.

The display is detected, is able to charge my laptop, and the rear USB ports are also working. The display will flash and show my desktop every time I reconnect the mini dp.

Any thoughts on what could be faulty here?

Answer this question I have this problem too

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Can you shine a flashlight at the display at an angle, do you see a faint image of your desktop? If you do then the backlight WLED driver is likely blown.

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Hi @danj, how would you go about replacing the backlight WLED driver on this display?

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Got the same problem. I solved it by buying a outlet switch. If you turn the screen off and on for a couple of times the picture will stay and keeps on running till you switch of your machine. So it's basically just a starting problem. Somestimes it takes about 5 min until the screen finally stays on - sometimes it works at the first time. I heard from an tech student that it's related to the logic control of the screen. So he said if I want to fix this I should buy another screen panel - not the logic board, because the logic control is in the screenpanel. At least that's what he said. I took the cheaper option and just bought an outlet switch for 2€ :)

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by the way: my screen was an ebay luck shot for 50€

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Thank you, thank you, thank you!!! Had the exact same problem and solved it by switching my Apple Cinema on and off several times.

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I have the exact same error, but it's intermittent and the problem mostly arises after power has been entirely disconnected from the display, i e disconnecting the power cable or switching an outlet off. As long as the computer just sleeps the display, it will often start up again.

When I get the flicker problem, sometimes one of two things helps to get it running again:

  • Connect it to a laptop and adjust the brightness setting of the Cinema Display. Results may not be instant, and doesn't always work but often does. You can try to lower it, then crank it up to max. (Note: the USB cable needs to be connected for the brightness setting to appear)
  • Like @janoslinde has done, connect it to an outlet with a powerswitch and try to power cycle it there. Often works for me.
  • Connected to a Mac mini that can be forced turned off, the display sometimes comes alive when cold starting the Mini again (this seems to give the display a different type of signal than when the computer sleeps and then wakes up)

At this point, I'm considering

  • Changing the logic board (around 120-200 EUR on eBay)
  • Getting a new Backlight WLED driver like @danj suggested
  • Changing the power supply (although multimeter reading shows it gives 24V, 12V, 5V, 3.3V just like it should). However it may be unstable, maybe some of the condensators bad? Costs around 100 EUR on eBay.
  • Possibly buying a new Function and/or Backlight cable (internal cables) although it seems unlikely it would be damaged and suddenly (and temporarily) go bad as to shut off the backlight.

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Added info: Actually when using the screen with my MBP, the screen was on for several hours but flickered (200ms flickers) twice during this time. Then suddenly it just went black.

I opened the display to test for 24V (which is supposedly driving the backlight), and it was still present. However, I may want to test for DC Amperes, since Volt doesn't give the full truth. I guess a bad capacitor on the PSU could still give the right volts, but not the right amperes.

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The power supply board may also be going bad. Does it work if you unplug power for a few minutes and then plug it back in? Usually it will work for 2-5 minutes and then the display will go black again.

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Sounds like the same problem I had. See:

What components need replacing on the Logic board?

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joro126 will be eternally grateful.
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